1. LIGO, ground-based Gravitational Wave Detectors
LIGO Livingston, LA (LLO)
LIGO Hanford, WA (LHO)
LIGO – Laser Interferometric Gravitational Wave Observatory
LSC – LIGO Scientific Collaboration, includes VIRGO (Italy) team, maybe India

2. Strain Curves from Moore et al.
Pulsar Timing Arrays
Spaced-based
Ground-based
1pc
30km
wavelength, m
3e16
3e12
3e8
3e4

3. Gravitational Wave Spectrum

5. LIGO Hardware LIGO “Test Mass” in 4-element suspension
LIGO Vacuum Tube
Ref: some hardware images

6. LIGO Hardware
LIGO “Test Mass” in suspension
Beam Splitter

7. Interference
Two arms, slightly different lengths, L and L+∆L, consider the amplitudes coming together.
Single amplitude like
Sum them together for

8. Nature of Gravitational Waves, and
Of all 10 possible components to h, it simplifies to two polarizations. One with a motion that shrinks (grows) in one direction while growing (shrinking) in the other direction. The other polarization is just rotated by 45 degrees.
hplus polarization
hcross polarization
Wave headed into the page, Y up, X right.

9. Effect of a perfectly aligned wave on LIGO

11. Seismic Noise aLIGO and initial

12. Pick out the Livingston Peaks in Above
Pick out the largest peaks, reconstruct the
possible noise.
Assumed at t=0 all the modes are in phase.
strain, 1e-21
0sec
3sec
3.0
strain, 1e-21
-3.0
1sec
1.5sec

13. Saulson, If Light Waves…
Argues that in the expanding Universe, light continuously experiences the increase in scale by expanding continuously itself.
NOT the case for a light wave in LIGO...
The wave filling the cavity IS stretched by the sudden onset of the gravitational wave.
but GW oscillates at 20 Hz, 50ms.
h_0 ΔL
time
Ref: Saulson, If Light Waves…, AmJPhys 65, 501 (1997)

14. As the Wave runs through...ΔL bb

15. Saulson, If Light Waves…, says rods are still rigid!

16. Strain Curve, Strain Sensitivity, Amplitude Spectral Density, Power Spectral Density...OH MY!
“per root Hz” is usually called the strain sensitivity, or sometimes amplitude spectral sensitivity

17. Strain Curve, etc... Characteristic Strain, just h
square root of Power Spectral Density, really amplitude spectral density
Ref: Cole,s online app .

18. Strain Curve, etc...
Power spectral Density bb

19. Links LIGO Scientific Collaboration, LSC LIGO Document Server
CalTech GW media assets page.
Kelly Holley-Bockelman’s TEDx Nashville Talk 2016 about GW
Pulsar timing array, Nanograv

20. Backup

21. LIGO Inteferometer
4km long

22. Units?

23. SI Prefixes

24. Gravitational Wave GW150914
Direct Discovery by LIGO of a gravitational wave announced on 11 February 2016 for a wave on 14 September event labeled GW
SNR = 24, 5 sigma detection!
Pretty after filtering out the known seismic frequencies.

25. Merging Black Holes
ref:

26. Schematic, Map, and Noise

27. GW strain for Circular Orbit
mass M_1, etc.
r is distance from Earth to system.
R is the separation of the two bodies.
ref: Maggiore around Eqn

28. Some Constants Schwarzschild radius 2GM/c^2 2953 m for Msun
GR Units, Mass
GM/c^2
1477 m for Msun
GR Units, Power
c^5/G
3.628e52 W
GR Units, Energy
c^4/G
1.210e44 J/m
parsec, pc
3.09e16 m = ly
astronomical unit, au
149.6e9 m
light-year, ly
0.946e16 m = pc
fine structure constant
e^2/(4pi eps0)/hbar c
= 1/137.04
wavelength-energy
h c
1.24 eV μm